The register_sidebars() WordPress PHP function allows you to create multiple sidebars for a theme or internally.
Usage
register_sidebars($number, $args);
Example:
register_sidebars(2, array('name' => 'Custom Sidebar %d'));
Parameters
$number(int, optional): Number of sidebars to create. Default is 1.$args(array|string, optional): Array or string of arguments for building a sidebar.id(string): The base string of the unique identifier for each sidebar. If provided, and multiple sidebars are being defined, the ID will have “-2” appended, and so on. Default is ‘sidebar-‘ followed by the number the sidebar creation is currently at.name(string): The name or title for the sidebars displayed in the admin dashboard. If registering more than one sidebar, include ‘%d’ in the string as a placeholder for the uniquely assigned number for each sidebar. Default is ‘Sidebar’ for the first sidebar, otherwise ‘Sidebar %d’.
More information
See WordPress Developer Resources: register_sidebars
Examples
Register one sidebar
This example registers a single sidebar named ‘Sidebar’.
register_sidebars();
Register two sidebars with custom names
This example registers two sidebars named ‘Foobar 1’ and ‘Foobar 2’.
register_sidebars(2, array('name' => 'Foobar %d'));
Register two sidebars with custom title HTML tags
This example registers two sidebars with the title wrapped in <h1> and </h1>.
register_sidebars(2, array('before_title' => '<h1>', 'after_title' => '</h1>'));
Register three sidebars with custom IDs
This example registers three sidebars with custom IDs.
register_sidebars(3, array('id' => 'custom-sidebar-'));
Register four sidebars with custom IDs and names
This example registers four sidebars with custom IDs and names.
register_sidebars(4, array('id' => 'custom-', 'name' => 'My Sidebar %d'));